// Copyright 2017 The Draco Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#ifndef DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_MESH_PREDICTION_SCHEME_TEX_COORDS_PORTABLE_DECODER_H_
#define DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_MESH_PREDICTION_SCHEME_TEX_COORDS_PORTABLE_DECODER_H_

#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_decoder.h"
#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_tex_coords_portable_predictor.h"
#include "draco/core/bit_coders/rans_bit_decoder.h"

namespace draco {

// Decoder for predictions of UV coordinates encoded by our specialized and
// portable texture coordinate predictor. See the corresponding encoder for more
// details.
template <typename DataTypeT, class TransformT, class MeshDataT>
class MeshPredictionSchemeTexCoordsPortableDecoder
    : public MeshPredictionSchemeDecoder<DataTypeT, TransformT, MeshDataT> {
  public:
    using CorrType = typename MeshPredictionSchemeDecoder<DataTypeT, TransformT,
          MeshDataT>::CorrType;
    MeshPredictionSchemeTexCoordsPortableDecoder(const PointAttribute *attribute,
            const TransformT &transform,
            const MeshDataT &mesh_data)
        : MeshPredictionSchemeDecoder<DataTypeT, TransformT, MeshDataT>(
              attribute, transform, mesh_data),
          predictor_(mesh_data) {}

    bool ComputeOriginalValues(const CorrType *in_corr, DataTypeT *out_data,
                               int size, int num_components,
                               const PointIndex *entry_to_point_id_map) override;

    bool DecodePredictionData(DecoderBuffer *buffer) override;

    PredictionSchemeMethod GetPredictionMethod() const override {
        return MESH_PREDICTION_TEX_COORDS_PORTABLE;
    }

    bool IsInitialized() const override {
        if (!predictor_.IsInitialized())
            return false;
        if (!this->mesh_data().IsInitialized())
            return false;
        return true;
    }

    int GetNumParentAttributes() const override {
        return 1;
    }

    GeometryAttribute::Type GetParentAttributeType(int i) const override {
        DRACO_DCHECK_EQ(i, 0);
        (void)i;
        return GeometryAttribute::POSITION;
    }

    bool SetParentAttribute(const PointAttribute *att) override {
        if (!att || att->attribute_type() != GeometryAttribute::POSITION)
            return false;  // Invalid attribute type.
        if (att->num_components() != 3)
            return false;  // Currently works only for 3 component positions.
        predictor_.SetPositionAttribute(*att);
        return true;
    }

  private:
    MeshPredictionSchemeTexCoordsPortablePredictor<DataTypeT, MeshDataT>
    predictor_;
};

template <typename DataTypeT, class TransformT, class MeshDataT>
bool MeshPredictionSchemeTexCoordsPortableDecoder<
DataTypeT, TransformT,
           MeshDataT>::ComputeOriginalValues(const CorrType *in_corr,
                   DataTypeT *out_data, int /* size */,
                   int num_components,
const PointIndex *entry_to_point_id_map) {
    predictor_.SetEntryToPointIdMap(entry_to_point_id_map);
    this->transform().Initialize(num_components);

    const int corner_map_size = this->mesh_data().data_to_corner_map()->size();
    for (int p = 0; p < corner_map_size; ++p) {
        const CornerIndex corner_id = this->mesh_data().data_to_corner_map()->at(p);
        predictor_.template ComputePredictedValue<false>(corner_id, out_data, p);

        const int dst_offset = p * num_components;
        this->transform().ComputeOriginalValue(predictor_.predicted_value(),
                                               in_corr + dst_offset,
                                               out_data + dst_offset);
    }
    return true;
}

template <typename DataTypeT, class TransformT, class MeshDataT>
bool MeshPredictionSchemeTexCoordsPortableDecoder<
DataTypeT, TransformT, MeshDataT>::DecodePredictionData(DecoderBuffer
        *buffer) {
    // Decode the delta coded orientations.
    int32_t num_orientations = 0;
    if (!buffer->Decode(&num_orientations) || num_orientations < 0)
        return false;
    predictor_.ResizeOrientations(num_orientations);
    bool last_orientation = true;
    RAnsBitDecoder decoder;
    if (!decoder.StartDecoding(buffer))
        return false;
    for (int i = 0; i < num_orientations; ++i) {
        if (!decoder.DecodeNextBit())
            last_orientation = !last_orientation;
        predictor_.set_orientation(i, last_orientation);
    }
    decoder.EndDecoding();
    return MeshPredictionSchemeDecoder<DataTypeT, TransformT,
           MeshDataT>::DecodePredictionData(buffer);
}

}  // namespace draco

#endif  // DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_MESH_PREDICTION_SCHEME_TEX_COORDS_PORTABLE_DECODER_H_
